Method for making polyurethane foam floor covering products with postconsumer carpet fibers

ABSTRACT

Polyurethane floor covering products are formed from a web layer containing at least 30% by weight fibers. A cooled polyurethane foam formulation which includes at least one polyisocyanate, water and at least one polyol having an equivalent weight of at least 500 is applied to the web layer. The wetted web layer is then compressed to mechanically wet out the fibers, gauged and heated to cure the foam formulation.

The present invention relates to methods for making polyurethane foamfloor covering products.

Used and discarded carpet products present a significant disposalproblem, due to the volume of these products that are removed fromoffice buildings, institutional settings and residences each year. Thesediscarded products are sent mainly to landfills where they take up largeamounts of landfill capacity. The fibers which comprise much of thecarpet weight are rarely biodegradable, and so the discarded carpet isexpected to remain more or less intact in the landfill for centuries.

Therefore, there is a stimulus towards recycling some or all of thefiber values that remain in discarded carpet products. To this end,various approaches have been developed to mechanically shred discardedcarpet products and recover some or all of the fiber values that theycontain. An example of such an approach is described in U.S. Pat. No.5,897,066.

Once the fiber values are recovered, there remains the problem of whatto do with them. The recovered fibers are not suitable for producing newcarpet facings, for several reasons. The recovered fibers tend to beheavily damaged due to wear and the recovery process itself. They areoften contaminated with other components of the carpet products, such assmall particles of a latex binder, inorganic filler particles, and thelike, which are hard to separate completely from the fibers. Inaddition, the fibers often have been dyed, and often are stained orcontain other absorbed contaminants.

Therefore, alternative uses are needed for these recovered fibers.

One potential use for these fibers is in underlayment cushion.Underlayment is widely installed under carpet materials to providecushioning. Because underlayment is concealed under the overlyingcarpet, its appearance is usually not important. Consumers resist payingsignificant amounts for a material that they cannot see, and so low costis a primary concern. Therefore, underlayment is often made ofinexpensive starting materials, including pieces of scrap foam which areformed and bonded together into a “rebond” material. Underlaymentapplications are therefore a potential application for fibers that arerecovered from post-consumer carpet products.

US Published Patent Application 2008/0075915, for example, describes acarpet underlayment that makes use of postconsumer carpet fibers. Thefibers are mixed with pieces of foam and a thermal binder, shaped into abatt, and heated to melt the binder and thereby adhere the variousconstituents to each other. The preferred binders in 2008/0075915 aresheath/core bicomponent fibers.

Other fiber-containing carpet underlayment products have been formed byimpregnating fibers with various types of binders. U.S. Pat. No.4,014,826, for example, describes a similar process similar to that of2008/0075915, in which a special type of fibers (which are notpost-consumer fibers) are used. A non-foaming latex or urethane is usedas the binder in U.S. Pat. No. 4,014,826. In GB 599682, GB 1,145,932,U.S. Pat. No. 3,480,456 and US Published Patent Application2006-0144012, needled fiber batts are impregnated with variousthermosetting and/or thermoplastic binder materials. In U.S. Pat. No.3,952,126, a mixture of polyurethane crumb and staple fibers is needledto form a batt. In U.S. Pat. No. 4,683,246, fiber filaments and foamcrumb are mixed with a polyurethane prepolymer and steam cured intobuns. U.S. Pat. No. 6,596,387 and US Published Patent Application2005-0126681 describe forming pad products by forming bi-layers ofpolyurethane or latex foam and fiber batts.

U.S. Pat. No. 4,269,889 and U.S. Pat. No. 4,296,054 describe moldedpolyurethane foams that are reinforced with polymer fibers to producemolded foam products for applications such as automotive seating. Apolyurethane foam formulation is introduced into a mold, followed by amass of entangled fibers of a special type. The polyurethane ispartially cured in the mold, and then demolded and postcured. Thismolding process can produce composites of polyurethane foam and fibers,but is not applicable for making large surface area products such ascarpet underlayment, as molds of the required dimensions are notavailable at any reasonable cost, and cure times are too long to befeasible in a floor covering manufacturing process. In addition, aspecial type of fibers is necessary in the process described in U.S.Pat. No. 4,269,889 and U.S. Pat. No. 4,296,054.

To date, none of the foregoing processes has been found to besatisfactory. Floor cushioning products must not only be manufacturedinexpensively, but they should also meet certain performance criteria.Among the performance criteria are an acceptable tear strength, lowcompression sets, adequate load bearing and the ability to retain itscushioning performance during foot trafficking.

This invention is a process for preparing a foamed polyurethane floorcovering product. The process comprises:

a) forming a web layer containing at least 30% by weight fibers, suchthat the web layer has a weight of from 150 to 600 g/m² and the fibersin the web layer have an average length of from 0.75 to 40 cm;

b) continuously applying a cooled polyurethane foam formulation whichincludes at least one polyisocyanate, water and at least one polyolhaving an equivalent weight of at least 500 to the web layer andcompressing the web layer and applied polyurethane foam formulationtogether to mechanically wet out the fibers in the web layer; and then

c) gauging the wetted web layer to a thickness of from 0.25 to 1.0inches and, while maintaining the gauge, heating the polyurethane foamformulation to a temperature of from 80 to 160° C. to cure thepolyurethane foam formulation to produce a cured and gauged polyurethanefoam cushion containing from 5 to 50% by weight of the fibers.

This process offers several advantages. Post-consumer fibers, such asthose obtained from discarded carpet, are entirely suitable for use inthe process. The polyurethane foam and the fibers become intimately andhighly uniformly distributed in the process, which leads to a producthaving highly uniform and consistent properties. The product can bemanufactured inexpensively; in particular, the foam formulation oftenfully cures in five minutes or less to produce a foam that exhibitsminimal roll set (as described more fully below). The fast cure makesthe process economically feasible to operate at an industrial scale,where large volumes of product must be made continuously and atcommercially reasonable line speeds. The fast cures also make theprocess feasible for making broadloom products which have widths of 6feet or more. In addition, a dense polyurethane skin often forms on oneor both surfaces of the product. This skin can make it unnecessary toattach a separate film layer to the surfaces of the product, as is oftendone with prior art underlayment products to prevent them from absorbingfluids, or for other reasons. The process is also versatile, andadaptable to manufacturing a variety of cushion products includingtraditional underlayment as well as attached cushion carpet products.

The process of the invention begins with the formation of a web layerthat contains fibers. The fibers may be formed into a web layer usingany convenient process such as various blowing and laydown methods, orby carding. “Carding” is used here in its usual context to mean that thefibers have been through a process which somewhat disentangles them andarranges individual fibers so that they become roughly parallel to eachother. The result is a lightweight “fluff” material similar in nature tocotton balls, although typically at a still lower weight per unitvolume. The fibers themselves are short fibers that have a weightaverage length of from 0.3 inches to 15 inches (0.75 cm to about 40 cm),preferably from 0.75 to 10 inches (1.9 to 25 cm). It is preferred thatat least 80 weight percent, more preferably at least 90 weight percentof the fibers have lengths between 0.75 inches and 10 inches (1.9 to 25cm).

The fibers are formed into a web layer, such that the weight of thelayer per unit area is from 150 to 600 g/m². The height of the web layerwill of course depend on the density of the web layer, which in turndepends mainly on how tightly the individual fibers are packed together.In general, the thickness of the web layer is generally approximatelyequal to or slightly larger than the thickness of the final product, orfrom about 0.25 to 1.0 inch thick, although the thickness may varysomewhat and may vary somewhat across the layer.

The web layer may be formed by depositing the fibers onto a suitablesurface of sufficient width. The fibers may be so deposited in acontinuous manner, immediately before the polyurethane foam formulationis applied to the layer, in effect integrating the step of forming theweb layer into a single operation with the remaining steps of theoverall process. Alternatively, the web layer can be made in apreliminary step, with the previously-formed web layer in that casebeing stored until needed.

The web layer may be needle-punched, heat-set or otherwise treated toentangle the fibers and thus increase its mechanical integrity.Similarly, various types of binders can be applied to the web layer forthe same reason. Suitable types of binders include various types ofbinder fibers as well as liquid, thermoplastic and/or thermosettingbinders. However, an advantage of this invention is that treatments suchas entanglement and/or the application of a binder are not necessary inorder to produce a good quality product, and those steps can be andpreferably are omitted from the process.

The fibers used to make the web layer can be any type that can withstandthe temperatures encountered in the curing step. Polymeric fibers suchas nylon or other polyamide, polypropylene, polyethylene, polyester, andthe like are all useful, as are natural fibers such as cotton, hemp orwool fibers. Carbon fibers can be used as well. Waste fibers fromindustrial processes also can be used, including, for example, selvedgetrimmings, yarn waste and the like. However, it is highly preferred,primary for reasons of cost and ecology, to use fibers that are obtainedfrom postconsumer carpeting products. These fibers preferably consist ofor are mainly fibers obtained from a cut or continuous loop pile of apile carpet. These pile fibers may be contaminated with particles of abinder material, which in the original carpet served to adhere thefibers to a backing or scrim material, as well as particles of inorganicmaterials such as clay, which is often used as a filler in bindercompositions that are used to construct pile carpets. The fibers mayalso contain parts of a backing or scrim material from the originalcarpet. The fiber denier is suitably from 5 to 50, and is morepreferably from 10 to 25.

The web layer may also contain other materials, in addition to thefibers. Such materials preferably are soft and flexible, so as not tointerfere with the cushioning properties of the product, and preferablyhave low densities. The other materials, if present, should be in theform of a particulate having a largest dimension of no greater thanabout 1 inch (2.5 cm) and preferably no greater than ½ inch (1.25 cm).Polymeric foams are useful additional materials, if ground or otherwiseformed into small pieces. Foamed natural or synthetic rubbers arepreferred types, including polyurethane foams. These polymeric foams canbe virgin materials, but it is preferred for reasons of cost and ecologyto use waste material or postconsumer materials. If these additionalmaterials are present in the web layer, the fibers should constitute atleast 30% and preferably at least 50% of the weight of the web layer.

A polyurethane foam formulation is applied to the web layer, and thewetted web layer is then compressed to mechanically wet out the fiberswith the polyurethane foam formulation. The manner of doing this is notconsidered to be critical to the invention, provided that thepolyurethane foam formulation becomes well-distributed within the weblayer. A convenient way to carry out these steps industrially is toposition the web layer on a moving platform, such as a conveyor belt,tenter frame or similar apparatus which permits the web layer to bemoved lengthwise relative to the point of application of thepolyurethane foam formulation and to apply the polyurethane foamformulation to the moving web layer. A traversing dispensing head, whichtravels back and forth across the width of the fiber web layer, can beused to distribute the polyurethane foam formulation onto the web layer.The layer is easily mechanically compressed by passing it under aroller, between rollers, or under a doctor blade. The web layer may becompressed to 5% to 35% of its original thickness, to force individualfibers into contact with the polyurethane foam formulation. It is oftenuseful to apply a layer of protective film onto the top of the wettedweb layer before compressing it, or as it is compressed, so that thedevice used to compress the film does not become contaminated with thepolyurethane foam formulation. Similarly, another layer of protectivefilm may be interposed between the web layer and the moving platform.

From about 1 to about 19 parts, preferably from 1 to 9 parts, and stillmore preferably from 2 to 5 parts by weight of the polyurethane foamformulation can be applied in this step, per part by weight of the weblayer.

The polyurethane foam formulation contains at least one polyisocyanate,water and at least one polyol having an equivalent weight of at least500, and may contain other components as well, as described more fullybelow. Polyurethane foam formulations of this type are highly reactive.Therefore, the polyurethane foam formulation is at most only partiallyformulated ahead of time, with the polyisocyanate being kept separatefrom the water, polyol and other isocyanate-reactive compounds untilimmediately before being dispensed. Once the polyisocyanate is mixedwith the water and the polyol, the gelling and blowing reactions whichform the foam begin to occur within a few seconds. The steps of applyingthe polyurethane foam formulation to the fiber web layer andmechanically compressing the wetted fiber web layer should be performedbefore the blowing and gelling reactions proceed to a significantextent. In most cases, these steps should be performed within 15 secondsof the time that the polyisocyanate is contacted with the water and thepolyol in the polyurethane foam formulation. It is more preferred toperform these steps with 10 seconds or within 7 seconds of that time.

The components of the polyurethane foam formulation are cooled beforemixing the together and applying the foam formulation to the web layer.The components preferably each have a temperature of less than 15° C.,more preferably 10° C. or less, at the time they are mixed. Any lowertemperature is suitable, provided that the components remain liquid andare not too viscous to process easily. It is usually not necessary tocool the components to below 0° C. This cooling slows the initialprogress of the blowing and gelling reactions, and so extends theprocess window for conducting the application and wetting steps. Oncethe components are mixed and the foam formulation begins to react, anexothermic reaction takes place which will increase the temperature ofthe formulation. The temperature of the foam formulation should be nomore than 20° C., preferably no more than 15° C. and still morepreferably no more than 12° C. when it first contacts the web layer.

The wetted web layer is then gauged to a thickness of from 0.25 to 1.0inches. The precise thickness will depend on the particular productbeing made, as well as the desired product density. Gauging isconveniently done by passing the wetted web layer under a roller orblade, or between a pair of nip rollers, or, more preferably, into adouble band laminator which is pre-set at the desired thickness.

Once gauged, the wetted web layer is heated to a temperature of from 80to 160° C. to cure the polyurethane foam formulation to produce a curedand gauged polyurethane foam cushion containing from 5 to 50% by weightof the carded fiber web. The gauge is maintained throughout the curingprocess, at least until such time as the foam formulation has curedenough that the cushion can maintain its gauge without applied pressureand exhibits an immediate roll set, measured as described below, of lessthan 10%. By “maintaining” a gauge, it is meant that the wetted weblayer is kept under mechanical pressure such that its thickness is keptat the desired value. This may be done, for example, by holding thewetted web layer between two heated platens for the requisite time, or,more preferably, by passing it though a double band laminator or similardevice which allows for continuous production. A double band laminatormay have heated platens which provide the needed curing temperature, ormay be installed in an oven or other heating device.

A preferred curing temperature is from 100 to 130° C. It may bedesirable to ramp the temperature upwardly over a period of time inorder to balance the blowing and gelling reactions in a way thatmaintains a good foam cell structure.

The curing time should be as short as practical, as shorter curing timestranslate to faster operating rates and lower production costs. It isgenerally preferred to selected the components of the polyurethanefoaming formulation and the curing temperature together such that thepolyurethane foam formulation cures, to the point where the productcushion can maintain its gauge without additional applied pressure andexhibits an immediate roll set of less than 10% (measured as describedbelow), within ten minutes and preferably within five minutes or lessfrom the time the polyurethane foam formulation is first contacted withthe web layer. In the preferred process, in which the wetted web layeris cured by passing it continuously through the gauging and heatingapparatus, the line speed and the length of the heating zone will beselected in conjunction with each other in order to provide sufficienttime to affect the cure.

If desired, a decorative or functional pattern can be impressed into thecushion during the curing step.

The cured product is then ready for rollup, or can be taken to otherdownstream operations. A number of downstream operations are possible,depending on the particular type of cushioning product beingmanufactured. For example, release films that may be used in themanufacturing process may be removed for disposal or reuse. One or moreadditional layers may be affixed to the cushion, using methods such asflame lamination, or gluing, or through some mechanical method. Theseadditional layers may be, for example, a reinforcing layer; a releaselayer, which permits the cushion to be easily removed from a floor in aglue-down installation; a carpet pile layer, synthetic grass layer orother type of show surface; a moisture barrier layer, an adhesive layer,and the like. These additional layers also can be attachedsimultaneously with the production of the foam cushion, by laying theweb layer atop the additional layer, and performing the subsequentprocess steps of wetting, gauging and dispensing on top of thatadditional layer. Alternatively or in addition, the wetted fiber weblayer can be formed, and an additional layer can be laid in on top ofthe wetted fiber web layer, before or after the gauging step, but beforethe polyurethane foam formulation has cured. It is noted that, because agood integral skin usually forms on the product, it is usuallyunnecessary to apply a moisture barrier or other skin material andbecause the embedded fibers provide good tear strength, reinforcementlayers often can be omitted from the product.

Other possible downstream operations include trimming, cutting tolength, cutting into desired shapes (such as to make floor tileproducts), application of various topical treatments, and the like.

Exclusive of these optional additional layers, the product cushiontypically has a bulk density of from about 2.5 to 15 pounds/cubic foot(40-240 kg/m³), preferably from 3 to 10 pounds/cubic foot (48-160 kg/m³)and more preferably from 4 to 8 pounds/cubic foot (64-128 kg/m³). Thefiber content may range from 5 to 50% by weight, is more preferably from10 to 50% by weight and still more preferably from 16 to 33% by weight.

Cushion products made in accordance with the invention and having bulkdensities and fiber contents as just mentioned, often have otherdesirable properties that make them suitable for a variety of floorcovering applications. They often have 50% compression sets of less than15%, as measured at 70° C. according to the method described below. Theyoften exhibit a 25% identation load deflection (ILD) of at least 14 kPa,preferably at least 20 kPa, up to 41 pKa, as measured according to themethod described below. They often retain greater than 30% and moretypically greater than 50% of their 25% ILD value when subjected to thesimulated foot traffic test described below.

The polyurethane-forming mixture includes at least one organicpolyisocyanate, which may be an aromatic, cycloaliphatic, or aliphaticisocyanate. Aromatic polyisocyanates are preferred and, among these,diphenylmethane diisocyanate (MDI) and/or a polymethylenepolyphenylisocyanate (PMDI) are preferred on the basis of generallygreater reactivity, availability and cost. MDI may be the 2,4′-isomer,the 4,4′-isomer, or some mixture thereof PMDI is generally a mixture ofone or polymethylene polyphenylisocyanates and some MDI; the MDI portionof the mixture may be either or both of the 2,4- and the 4,4′-isomers.Prepolymers can be formed from any of the foregoing polyisocyanates byreacting an excess of the polyisocyanate with a polyol, aminoalcohol orpolyamine. A preferred type of prepolymer is described in EP 485,953B.The polyisocyanate is generally used in an amount sufficient to providean isocyanate index of from about 0.85 to 1.5, preferably from 0.9 to1.25.

The polyurethane foam formulation also includes at least one polyol thathas an equivalent weight (per hydroxyl group) of at least 500. Two ormore such polyols may be present. The equivalent weight of this polyolis preferably from about 750 to 3000, and more preferably from 1000 to2000. The polyol should have an average of from about 1.8 to 4,preferably from about 2 to about 3, hydroxyl groups per molecule. Thepolyol may have secondary hydroxyl groups or primary hydroxyl groups, orsome combination thereof; however, it is preferred that at least 50% ofthe hydroxyl groups, and more preferably at least 80% of the hydroxylgroups, are primary hydroxyl groups, as these are more reactive towardsisocyanate groups and thus allow the formulation to cure faster. Thesepolyols may be polyester polyols, polyether polyols, polyols that areprepared from vegetable oils and/or fatty acids, or other types.Polyether polyols are preferred, especially polymers of propylene oxidewhich contain from 5 to 25% by weight of terminal poly(ethylene oxide)blocks.

An especially preferred type of polyol is an amine-initiated polyol thatcontains primarily primary hydroxyl groups, such as those described inU.S. Pat. No. 6,762,274.

The polyurethane foam formulation also includes water, which reacts withthe polyisocyanate to simultaneously generate a blowing gas (carbondioxide) and to build molecular weight though the formation of urealinkages. Water is generally present in an amount from about 2 to about7 parts by weight per 100 parts by weight of the polyol(s) that have anequivalent weight of 500 or more. A preferred amount is from 3 to 6parts, on the same basis.

The polyurethane foam formulation may contain various other components,in addition to the aforementioned polyisocyanate, polyol and water.

A catalyst is preferably present. A wide variety of amine and organotincatalysts are suitable, including include di-n-butyl tinbis(mercaptoacetic acid isooctyl ester), dimethyltin dilaurate,dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, stannousoctoate, lead octoate, nickel acetylacetonate, ferric acetylacetonate,bismuth carboxylates, triethylenediamine, N-methyl morpholine, likecompounds and mixtures thereof. An amine-blocked tin (IV) catalyst, suchas those described in U.S. Pat. No. 5,491,174, can be used. It isgenerally not desirable to use a delayed action catalyst, in view of theneed for a rapid cure once the wetting step has been completed. If anorganometallic catalyst is employed, it is generally present in anamount from about 0.01 to about 0.5 parts per 100 parts of thepolyurethane foam formulation, by weight. If a tertiary amine catalystis employed, the catalyst preferably is present in an amount from about0.01 to about 3 parts of tertiary amine catalyst per 100 parts of thepolyurethane-foam formulation, by weight.

The polyurethane foam formulation may include at least one surfactant,which serves to stabilize the foam bubbles until the composition hascured. Organosilicone surfactants, such as those described in U.S. Pat.No. 4,483,894, are preferred. If a surfactant is present, it is typicalto include up to about 3 parts of surfactant per 100 parts by weightpolyols. However, one surprising benefit of this invention is that thesurfactant can often be omitted, while still producing a good qualityfoam having a reasonably uniform cell structure.

One or more crosslinkers, by which it is meant a compound having atleast three isocyanate-reactive groups and an equivalent weight perisocyanate-reactive group of up to 499, preferably up to 250, may bepresent in the polyurethane foam formulation. A chain extender, by whichit is meant a compound having exactly two isocyanate-reactive groups andan equivalent weight per isocyanate-reactive group of up to 499,preferably up to 250, also may be present. Crosslinkers and chainextenders are usually used in small amounts, such as up to 20,preferably up to 5 and more preferably up to 2 parts by weight per 100parts by weight of polyol(s) having an equivalent weight of 500 or more.Examples of suitable crosslinkers and chain extenders includetriethanolamine, diethanolamine, monoethanolamine, glycerine,trimethylolpropane, pentaerythritol, ethylene glycol, diethylene glycol,triethylene glycol, propylene glycol, dipropylene glycol, tripropyleneglycol, 1,4-dimethylolcyclohexane, 1,4-butane diol, 1,6-hexane diol,1,3-propane diol, diethyltoluene diamine, amine-terminated polyetherssuch as Jeffamine D-400 from Huntsman Chemical Company, amino ethylpiperazine, 2-methyl piperazine, 1,5-diamino-3-methyl-pentane,isophorone diamine, ethylene diamine, hexane diamine, hydrazine,piperazine, mixtures thereof and the like. Amine crosslinkers and chainextenders can be blocked, encapsulated, or otherwise rendered lessreactive in order to reduce the initial reactivity of the formulationand provide more working time to apply and gauge the foam layer.

The polyurethane-foam formulation may include a filler, which reducesoverall cost and may improve flame resistance, firmness and otherphysical properties to the product. The filler may constitute up toabout 50 percent of the total weight of the polyurethane foamformulation. Suitable fillers include talc, mica, montmorillonite,marble, barium sulfate (barytes), milled glass granite, milled glass,calcium carbonate, aluminum trihydrate, carbon, aramid, silica,silica-alumina, zirconia, talc, bentonite, antimony trioxide, kaolin,fly ash and boron nitride.

Other additives may be used, including fire retardants, pigments,antistatic agents, reinforcing fibers, antioxidants, preservatives, acidscavengers, and the like.

The cushioning product can be used as carpet underlayment, in home,office, industrial, institutional or other settings. In this regard, itcan be installed and used in the same manner as conventional carpetpadding products. As mentioned, the cushioning product may take the formof an attached cushion, on the underside of a woven or tufted carpetproduct. The cushioning product is also useful for other padding andcushioning application, including, for example, furniture pads andvarious packaging applications.

EXAMPLE 1

A formulated polyol mixture is prepared by mixing 1200 parts by weightof a 1700 equivalent weight, nominally trifunctional, amine-initiatedpolyol, which is prepared according to the general process of U.S. Pat.No. 6,762,274, 12 parts of an 85% solution of diethanolamine in water,43.7 parts water and 18 parts of a 33% solution of triethylenediamine indipropylene glycol. These are mixed thoroughly and cooled to 7° C.

Shredded post consumer carpet fibers, containing mainly nylon fibersabout 8.5+/−4.8 cm in length, are carded and formed into a 30.5×30.5layer weighing 20.9 g. This web layer is sandwiched between two layersof polyethylene release film, and placed into a 30.5 cm×30.5 cm×1.11 cmopen-top mold which is preheated to 121° C. The web layer is heated inthe mold for 30 minutes to drive off residual water from the layer andcooled back down to ambient temperature. The top release film layer ispulled back, and a 3500 g, 30.4-cm long roller having a diameter or 4.5cm is placed at one end of the open mold. 104.64 g of the cooled polyolmixture is mixed with 66.08 g of a cooled (7° C.) PMDI product having anisocyanate content of 29.4% (SPECFLEX™ NE 134 isocyanate, from The DowChemical Company), and 65 g of the resulting polyurethane foamformulation is immediately poured over the carded fiber web in the mold.The release film is replaced, and the roller is pulled down across themold on top of the release film, compressing the fiber web and causingthe individual fibers to become wetted with the polyurethane foamformulation. The top is then placed onto the mold, the mold is placed ina 121° C. oven, and the polyurethane foam formulation is allowed to curefor five minutes at 121° C. The mold is removed from the oven and thesample is removed. The sample is aged for 7 days under the conditionsspecified in ASTM 3675-78 for performance property testing. Density,compression set and sample thickness are measured according to ASTM3675-78. ILD is measured according to ASTM 3574-78.

Compression set is measured as follows. 2″×2″ (5 cm×5 cm) foam specimensare formed into 2 stacks of plied specimens each approximately 1 inch(2.5 cm) thick. The stack is placed in an Instron tensile testing deviceequipped with a circular presser foot one square inch (6.45 cm²) inarea, and the thickness of the specimen is measured at an applied loadof 100 grams per square inch (100 g/6.45 cm²)

The specimen is then compressed to 50% of its original thickness betweentwo parallel plates which are each larger than the specimen area. Thespecimen is then held at this compressed thickness and heated in acirculating air oven at 70° C. for 22 hours.

The specimen is then removed from the oven and allowed to re-expand. Itis returned to the oven for 0.5 hour, and then allowed to cool for 5 to10 minutes. The thickness is then remeasured as before. The compressionset is calculated as

C _(f)=100(t _(o) −t _(f))/t _(o)

where C_(f) is the compression set, t_(o) is the original thickness andt_(f) is the final specimen thickness.

Ball rebound is determined according to ASTM D3574-86 Test Method H,modified in that the sample size is 2×6 inches (2.5×15 cm), and theheight of the sample is built up to about 1 inch (2.5 cm) by stackingmultiple layers of the composite.

25% ILD is measured as follows. Enough 2″×6″ (2.5×15 cm) skivedcomposite specimens are stacked to form a stack of plied specimens eachapproximately 1 inch (2.5 cm) thick. The stack is placed in an Instrontensile testing device equipped with a circular presser foot one squareinch (6.45 cm²) in area, and the thickness of the specimen is measuredat an applied load of 100 grams per square inch (100 g/6.45 cm²). Thespecimen is compressed to 75% of its original thickness, using the onesquare inch pressure foot, and the load required to so compress thespecimen is determined. This reading is the compression resistance ofthe foam. The procedure is repeated on a duplicate stack and the resultsare averaged.

Retention of 25% ILD is determined as follows. 25% ILD is measured on asample as described above. The sample is then subjected to 12,000compression cycles on a Hexapod tester, which simulates repeated foottraffic over the sample, and 25% ILD is re-measured as before. Theretention of 25% ILD is calculated as the second 25% ILD measurement asa percentage of the initial 25% ILD measurement.

Results of the foregoing testing are as indicated in Table 1. Theproperties of a commercially available rebond carpet underlaymentproduct are given for comparison.

TABLE 1 Example Commercial Rebond Property 1 Underlayment Cure time,min. 5 NA Sample weight, g/m² 1016 1098 Post-consumer fiber content, %22 0 Pad density, kg/m³ 80.4 96.4 Thickness, mm 12.6 11.3 25% ILD, kPa25.5 22 50% compression set, % 15 14 Ball rebound, % 41 30 25% ILDretention, % 60 54

The data in Table 1 shows that Example 1 has an ILD, compression set andball rebound values that closely approximate those of the commercialrebond material, even though the density and pad weight are lower forExample 1, and even though Example 1 contains a significantpost-consumer fiber content. The ILD retention for Example 1 is betterthan that of the commercial rebond material, too.

Despite the absence of a surfactant, the cushion has a good uniform cellstructure and good properties.

EXAMPLE 2

Example 1 is repeated, using the following formulated polyol mixtureinstead of that described in Example 1:

1030 equivalent weight, nominally trifunctional, random 19 partscopolymer of 87% propylene oxide and 13% ethylene oxide: 1550 equivalentweight, nominally trifunctional ethylene 81 parts oxide-cappedpoly(propylene oxide) having 88% primary hydroxyl groups 85% solution ofdiethanolamine in water: 0.6 parts Silicone surfactant: 1.5 parts Water:3.61 parts 33% solution of triethylenediamine in dipropylene glycol:0.17 parts 30% bis(dimethylaminoethyl)ether in dipropylene glycol: 0.12parts

Conditions otherwise are identical to those of Example 1, except themold temperature is only 100° C.

Properties are measured as for Example, with the results being asindicated in Table 2:

TABLE 2 Property Example 1 Cure time, min. 5 Sample weight, g/m² 997Post-consumer fiber content, % 28 Pad density, kg/m³ 72.4 Thickness, mm12.7 25% ILD, kPa 15.1 50% compression set, % 15 Ball rebound, % 35.725% ILD retention, % 77.5

1. A process for preparing a foamed polyurethane floor covering product,comprising: a) forming a web layer containing at least 30% by weightfibers, such that the web layer has a weight of from 150 to 660 g/m² andthe fibers in the web layer have an average length of from 0.75 to 40cm; b) continuously applying a cooled polyurethane foam formulationwhich includes at least one polyisocyanate, water and at least onepolyol having an equivalent weight of at least 500 to the web layer, thecooled polyurethane foam formulation having a temperature of no morethan 15° C. when applied to the web layer, and compressing the web layerand applied polyurethane foam formulation together to mechanically wetout the fibers in the web layer; and then c) gauging the wetted weblayer to a thickness of from 0.25 to 1.0 inches and, while maintainingthe gauge, heating the polyurethane foam formulation to a temperature offrom 80 to 160° C. to cure the polyurethane foam formulation to producea cured and gauged polyurethane foam cushion containing from 5 to 50% byweight of the fibers.
 2. The process of claim 1, wherein the cooledpolyurethane foam formulation has a temperature of not more than 10° C.when applied to the web layer.
 3. The process of claim 1, wherein theweb layer contains at least 50% by weight of fibers.
 4. The process ofclaim 1, wherein the web layer further contains at least 50% by weightof fibers.
 5. The process of claim 1, wherein the web layer comprisescarded fibers.
 6. The process of claim 1, wherein the fibers areobtained from postconsumer carpeting products.
 7. The process of claim1, wherein the foamed polyurethane floor covering product has a densityof from 3 to 10 pounds/cubic foot (48-160 kg/m³).
 8. A foamedpolyurethane floor covering product produced by the process of claim 1.9. The product of claim 8 which contains from 5 to 30% of fibers.